More high schools than ever — 240, or 48 percent — earned A grades, while the number of F-graded schools rose from 3 to 8. So many schools received A's and B's that the state will increase its scoring levels next year.

"It is important that we continue to raise the bar as Florida has done over the years," education commissioner Pam Stewart said in a conference call with reporters. "Our students benefit whenever we do that."

More than half the high schools in Hillsborough and Pinellas counties received A's. And Pinellas marked a first, with no high school earning below a B.

But beyond those numbers, the results were mixed. While six Pinellas schools raised their grades, three lost their A's. In Pasco County, five schools saw their grades rise, while five declined and three remained the same. Hernando County tasted disappointment, with all its high schools dropping a grade.

The results emerged as the state changed its accountability system, with harder tests, higher passing scores and new standards in place.

To protect schools from wild swings in grades while the system remains in flux, the State Board of Education renewed a "safety net" so no school dropped more than one letter grade. That cushion helped seven high schools statewide.

The rapidity of changes to the system has prompted teachers, superintendents and even State Board members to question the value of Florida's A-F grades. More alterations are planned as Florida transitions to new state standards known as Common Core.

Few have gone so far as to call for an end to the grading, but many leaders have pressed for the state to slow its accountability effort to give teachers and students time to make a proper transition to new exams, standards and expectations.

The state superintendents association is set to meet with Stewart on Thursday to discuss ways to move away from the current program, which the association has said is "no longer credible in the eyes of the public."

Pasco assistant superintendent Amelia Larson called the high school grades the least questionable of the bunch, because they take into account criteria such as dropout rates and participation in advanced coursework.

"For me, this is a much better picture of what is going on," Larson said. "It's more than a one-day snapshot."

Two Pasco schools lost a letter grade for failure to make adequate academic progress with students at risk of dropping out. Land O'Lakes High, with more than enough points to earn an A, fell victim to that criterion.

"That tells me right there I need to work with my schools for that subgroup," Larson said.

Superintendents Mike Grego of Pinellas and MaryEllen Elia of Hillsborough agreed that high school grades are more meaningful. Grego said they encompass students' experience from the day they enter ninth grade, "all the way to when they graduate in 12th."

In his district, Pinellas Park, Largo and Countryside high schools all lost their top marks, earning B grades. But Clearwater, Dunedin and Lakewood all got their first A's. Three other schools — Dixie Hollins, Gibbs and Northeast — improved their C's to B's.

Lakewood principal Bob Vicari said he kept a "war room" next to his office with the name of every struggling student to track their progress.

"It changes the whole school climate," Vicari said. "When I first came here four years ago, you could feel like students felt like it wasn't a great school. And now, and each year, the climate's changed. Everyone's celebrating."

In Hillsborough County, 14 of the district's 27 high schools received A grades Wednesday.

"It certainly takes a lot of hard work and it doesn't come easily," Elia said at a news conference, joined by five principals.

"We have to make sure every kid and every class counts," said Johnny Bush, the principal at Robinson High , which got its second consecutive A.

All five Hernando County high schools dropped a letter grade, with no high schools earning an A.

At Weeki Wachee High, where the score was based only on limited state assessments the previous year, the school grade dropped from an A to a B in its first grade that reflected a graduating class. The school was protected from dropping even more by the state's safety net.

Hernando superintendent Lori Romano said the grades came as a disappointment to the district's high school principals.

"They're working hard," she said. "I think it's frustrating for the principals and their teams."

She said she was surprised by the drop at Springstead, which struggled with its at-risk population. Principal Susan Duval noted her school has been penalized under this rule before.

"I think it's outrageous," she said. "It makes us appear less than what we are. And we are an A."

Romano said the district will begin drilling down into the data, analyzing it and continuing to focus on excellence.

"We're going to go full-speed ahead," she said. "It can't continue to be business as usual."